1. Field of the Invention
The present invention generally relates to catalyst carriers.
2. Discussion of the Background
Conventionally, various exhaust gas processing devices for internal combustion engines of vehicles, construction machinery, or the like have been suggested, and these have been used in practice. A typical exhaust gas processing device has a casing made of, for example, metal or the like on an exhaust pipe connected to an exhaust gas manifold of the engine. A honeycomb structure is provided in the casing. This honeycomb structure composes a catalyst carrier configured to convert harmful gas or the like in exhaust gas by catalytic reaction.
This catalyst carrier is manufactured by, for example, supporting a catalyst carrier layer such as γ-aluminum and a catalyst such as platinum at a cell wall of a cordierite honeycomb structure having low thermal expansion properties. Harmful gas such as CO, HC, and NOx contained in the exhaust gas is converted by the catalyst provided at the cell wall.
In the catalyst carrier having such a honeycomb structure, in order to improve its converting ability of the exhaust gas, it is necessary to improve the contact ratio of the exhaust gas and the catalyst such as a noble metal. As a catalyst carrier to solve such a problem, a honeycomb structure made of a high specific surface area material such as aluminum and inorganic fibers and having a high specific surface area has been suggested in, for example, Japanese Unexamined Patent Application Publication Nos. 2005-218935 and 2005-349378.
These Japanese Publications No. 2005-218935 and No. 2005-349378 are hereby incorporated herein by reference in their entirety.